The Illusion Butterfly is formidable, but incredibly difficult to reproduce. As an advanced magical beast, the gestation itself is challenging, and even if conceived, there are only three or four eggs. Moreover, these eggs can only hatch smoothly if the mother butterfly personally guards and incubates them.
However, Illusion Butterfly eggs often end up outside the protection of the mother due to various accidents. Without the mother's care, the chances of these eggs hatching are nearly impossible, unless a human cultivator patiently feeds them spiritual energy daily. Even then, the likelihood of success is less than one in a thousand.
Thus, although Illusion Butterfly eggs are precious, their price isn't high because the chances of successful hatching are extremely low. Therefore, the Illusion Butterfly egg given to Tan Shuangshuang for a spiritual pearl is considered a fair price, given its rarity and the difficulty in obtaining it.
